Commonplace Book
A collection of research notes across various topics, culminated in one book (books were expensive!), sorted by Tags or Topics
Historically, commonplace books were a way to collect research from books that were too scarce to leave the library/collection they belonged in, so you had to copy your own quotes & ideas into your book that you took with you.
Overtime, people would also use commonplace books to store their favourite notes, quotes, and ideas in a single (common) area (place). Hence the name.
I am using my commonplace book to solve 🌱 My 12 Favourite Problems